Modern inorganic chemistry

H

X •

N;

• x
  H
  gas gas

STRUCTURE AND BONDING

H

H;N*H

• X
  H
  ammonium ion chloride ion
  as solid ammonium chloride

43

i.e.

H

H N"

/"

H

/\^H/ i I

cr

The strongly electronegative (p. 49) chlorine atom becomes a

chloride ion, the proton H^ accepting the electron pair donated by

the nitrogen atom. A similar reaction occurs when ammonia is

passed into water, but to a much lesser extent as oxygen in water is

a poorer donor of the electron pair:

H H H

A-H + V - Y- H--?-

/

+

/o H^'"

H

V

H H H H

(ammonia hydrate"-weakly associated

through hydrogen bonding, p 52;

H

N

,*t

The positive charge resulting from the addition of a proton on to
an ammonia molecule is not associated with any particular hydro-
gen atom, once the bond is formed, and is distributed over the
whole ion.

Oxo-acid anions

There are many simple examples of common covalently bonded oxo-
anions, some being: COj~, NO^, SO^ and PO|~. The carbonate